Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 1 | /* |
| 2 | * trace event based perf counter profiling |
| 3 | * |
| 4 | * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com> |
| 5 | * |
| 6 | */ |
| 7 | |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 8 | #include <linux/module.h> |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 9 | #include "trace.h" |
| 10 | |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame^] | 11 | /* |
| 12 | * We can't use a size but a type in alloc_percpu() |
| 13 | * So let's create a dummy type that matches the desired size |
| 14 | */ |
| 15 | typedef struct {char buf[FTRACE_MAX_PROFILE_SIZE];} profile_buf_t; |
| 16 | |
| 17 | char *trace_profile_buf; |
| 18 | char *trace_profile_buf_nmi; |
| 19 | |
| 20 | /* Count the events in use (per event id, not per instance) */ |
| 21 | static int total_profile_count; |
| 22 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 23 | static int ftrace_profile_enable_event(struct ftrace_event_call *event) |
| 24 | { |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame^] | 25 | char *buf; |
| 26 | int ret = -ENOMEM; |
| 27 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 28 | if (atomic_inc_return(&event->profile_count)) |
| 29 | return 0; |
| 30 | |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame^] | 31 | if (!total_profile_count++) { |
| 32 | buf = (char *)alloc_percpu(profile_buf_t); |
| 33 | if (!buf) |
| 34 | goto fail_buf; |
| 35 | |
| 36 | rcu_assign_pointer(trace_profile_buf, buf); |
| 37 | |
| 38 | buf = (char *)alloc_percpu(profile_buf_t); |
| 39 | if (!buf) |
| 40 | goto fail_buf_nmi; |
| 41 | |
| 42 | rcu_assign_pointer(trace_profile_buf_nmi, buf); |
| 43 | } |
| 44 | |
| 45 | ret = event->profile_enable(); |
| 46 | if (!ret) |
| 47 | return 0; |
| 48 | |
| 49 | kfree(trace_profile_buf_nmi); |
| 50 | fail_buf_nmi: |
| 51 | kfree(trace_profile_buf); |
| 52 | fail_buf: |
| 53 | total_profile_count--; |
| 54 | atomic_dec(&event->profile_count); |
| 55 | |
| 56 | return ret; |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 57 | } |
| 58 | |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 59 | int ftrace_profile_enable(int event_id) |
| 60 | { |
| 61 | struct ftrace_event_call *event; |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 62 | int ret = -EINVAL; |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 63 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 64 | mutex_lock(&event_mutex); |
Steven Rostedt | a59fd60 | 2009-04-10 13:52:20 -0400 | [diff] [blame] | 65 | list_for_each_entry(event, &ftrace_events, list) { |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 66 | if (event->id == event_id && event->profile_enable && |
| 67 | try_module_get(event->mod)) { |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 68 | ret = ftrace_profile_enable_event(event); |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 69 | break; |
| 70 | } |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 71 | } |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 72 | mutex_unlock(&event_mutex); |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 73 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 74 | return ret; |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 75 | } |
| 76 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 77 | static void ftrace_profile_disable_event(struct ftrace_event_call *event) |
| 78 | { |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame^] | 79 | char *buf, *nmi_buf; |
| 80 | |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 81 | if (!atomic_add_negative(-1, &event->profile_count)) |
| 82 | return; |
| 83 | |
| 84 | event->profile_disable(); |
Frederic Weisbecker | 20ab4425 | 2009-09-18 06:10:28 +0200 | [diff] [blame^] | 85 | |
| 86 | if (!--total_profile_count) { |
| 87 | buf = trace_profile_buf; |
| 88 | rcu_assign_pointer(trace_profile_buf, NULL); |
| 89 | |
| 90 | nmi_buf = trace_profile_buf_nmi; |
| 91 | rcu_assign_pointer(trace_profile_buf_nmi, NULL); |
| 92 | |
| 93 | /* |
| 94 | * Ensure every events in profiling have finished before |
| 95 | * releasing the buffers |
| 96 | */ |
| 97 | synchronize_sched(); |
| 98 | |
| 99 | free_percpu(buf); |
| 100 | free_percpu(nmi_buf); |
| 101 | } |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 102 | } |
| 103 | |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 104 | void ftrace_profile_disable(int event_id) |
| 105 | { |
| 106 | struct ftrace_event_call *event; |
| 107 | |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 108 | mutex_lock(&event_mutex); |
Steven Rostedt | a59fd60 | 2009-04-10 13:52:20 -0400 | [diff] [blame] | 109 | list_for_each_entry(event, &ftrace_events, list) { |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 110 | if (event->id == event_id) { |
Frederic Weisbecker | e5e25cf | 2009-09-18 00:54:43 +0200 | [diff] [blame] | 111 | ftrace_profile_disable_event(event); |
Li Zefan | 558e654 | 2009-08-24 12:19:47 +0800 | [diff] [blame] | 112 | module_put(event->mod); |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 113 | break; |
| 114 | } |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 115 | } |
Li Zefan | 20c8928 | 2009-05-06 10:33:45 +0800 | [diff] [blame] | 116 | mutex_unlock(&event_mutex); |
Peter Zijlstra | ac199db | 2009-03-19 20:26:15 +0100 | [diff] [blame] | 117 | } |